What is the chemical that dentists use to bleach or whiten the teeth?

Hi:Normally hydrogen or carbamide peroxide is used to whiten teeth.  Whitening is best done in absence of gum imflamation.  If your gums are inflamed its best to get the cleaning done first and wait a week before whitening.Best,Dr. Maddahi

The active ingredient is carbamide peroxide. Usually a good idea to wait a week or more before whitenng after a cleaning is done.

Hello, the most common components are hydrogen peroxide or carbamide peroxide, it is not recommended to apply any kind of dental whitening immediately after scaling or in any case with inflamed gingiva (gums), because the product used to protect your gums might not adhere properly to it. Its always a good idea to allow at least 24 hrs after a cleaning or scaling before going to whitening to prevent a chemical burn (even if tiny) to your soft tissue.